MicroRNA-454 Contributes to Sustaining the Proliferation and Invasion of Trophoblast Cells Through Inhibiting Nodal/ALK7 Signaling in Pre-eclampsia

MicroRNAs (miRNAs) are emerging as important regulators in the pathogenesis of pre-eclampsia (PE). Recent evidence has reported that miR-454 plays an important role in regulating cell proliferation and invasion. The decreased proliferation and invasion of trophoblast cells contribute to the pathogenesis of PE. However, whether miR-454 is involved in the regulation of trophoblast cell proliferation and invasion remains unknown. In this study, we aimed to investigate the potential role and underlying mechanism of miR-454 in regulating trophoblast cell proliferation and invasion in vitro. We found that miR-454 expression was significantly decreased in placental tissues from PE patients compared to controls. Transfection of miR-454 mimics promoted the proliferation, reduced the apoptosis, and increased invasion of trophoblast cells, while transfection of miR-454 inhibitor showed opposite effects. Bioinformatics analysis showed that activin receptor-like kinase 7 (ALK7) was a potential target gene of miR-454. Dual-luciferase reporter assay showed miR-454 directly targeted the 3'-untranslated region of AKL7. Further experiments showed that miR-454 negatively regulated ALK7 expression. Interestingly, transfection of miR-454 mimics significantly abrogated the inhibitory effect of Nodal on trophoblast cell proliferation and invasion. Moreover, overexpression of ALK7 markedly reversed the promotion effect of miR-454 on trophoblast cell proliferation and invasion. Overall, our results suggest that miR-454 promotes the proliferation and invasion of trophoblast cells by downregulation of ALK7. Our study suggests that miR-454 may play critical roles in the pathogenesis of PE and serve as a potential therapeutic target for treatment of PE.